The present invention relates to an optical combiner and a laser device using the same, which are preferable to the case of suppressing heat generation or ignition caused by return light.
Heretofore, for an optical combiner that combines light beams emitted from a plurality of laser light sources with a single optical fiber, Patent Document 1 described below is proposed, for example.
In the multiport coupler described in Patent Document 1, a signal fiber 5 in the center is integrated with a plurality of pump fibers 4 disposed around the signal fiber 5, and the diameter is reduced on the tip end side. An emitted-light confinement waveguide 7 is concentrically provided around a core 6 of the signal fiber 5 positioned in the center. The emitted-light confinement waveguide 7 has the outer diameter greater than the outer diameter of the core 6, and has the refractive index higher than the refractive index of the cladding 8 and smaller than the refractive index of the core 6.
The emitted-light confinement waveguide 7 confines return light leaking from the core of a cladding pump fiber 3 at the portion at which the cladding pump fiber 3 is connected to the end portion on the diameter reduced side, and suppresses the damage of a pumping light source caused by the return light.    [Patent Document 1] Japanese Patent No. 5089950